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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* 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>
David Howells76d8aea2005-06-23 22:00:49 -070021#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#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
David Howells664cceb2005-09-28 17:03:15 +010038#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 */
David Howells29db9192005-10-30 15:02:44 -080043#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
44#define KEY_POS_ALL 0x3f000000
David Howells664cceb2005-09-28 17:03:15 +010045
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
David Howells29db9192005-10-30 15:02:44 -080051#define KEY_USR_SETATTR 0x00200000
52#define KEY_USR_ALL 0x003f0000
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
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
David Howells29db9192005-10-30 15:02:44 -080059#define KEY_GRP_SETATTR 0x00002000
60#define KEY_GRP_ALL 0x00003f00
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
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
David Howells29db9192005-10-30 15:02:44 -080067#define KEY_OTH_SETATTR 0x00000020
68#define KEY_OTH_ALL 0x0000003f
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
70struct seq_file;
71struct user_struct;
72struct signal_struct;
73
74struct key_type;
75struct key_owner;
76struct keyring_list;
77struct keyring_name;
78
79/*****************************************************************************/
80/*
David Howells664cceb2005-09-28 17:03:15 +010081 * 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
111/*****************************************************************************/
112/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 * 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 struct rw_semaphore sem; /* change vs change sem */
125 struct key_user *user; /* owner of this key */
David Howells29db9192005-10-30 15:02:44 -0800126 void *security; /* security data for this key */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 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 */
David Howells76d8aea2005-06-23 22:00:49 -0700132 unsigned short datalen; /* payload data length
133 * - may not match RCU dereferenced payload
134 * - payload should contain own length
135 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
137#ifdef KEY_DEBUGGING
138 unsigned magic;
139#define KEY_DEBUG_MAGIC 0x18273645u
140#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
141#endif
142
David Howells76d8aea2005-06-23 22:00:49 -0700143 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 /* 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;
163 } type_data;
164
165 /* key data
166 * - this is used to hold the data actually used in cryptography or
167 * whatever
168 */
169 union {
170 unsigned long value;
171 void *data;
172 struct keyring_list *subscriptions;
173 } payload;
174};
175
176/*****************************************************************************/
177/*
178 * kernel managed key type definition
179 */
David Howellsb5f545c2006-01-08 01:02:47 -0800180typedef int (*request_key_actor_t)(struct key *key, struct key *authkey, const char *op);
181
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182struct key_type {
183 /* name of the type */
184 const char *name;
185
186 /* default payload length for quota precalculation (optional)
187 * - this can be used instead of calling key_payload_reserve(), that
188 * function only needs to be called if the real datalen is different
189 */
190 size_t def_datalen;
191
192 /* instantiate a key of this type
193 * - this method should call key_payload_reserve() to determine if the
194 * user's quota will hold the payload
195 */
196 int (*instantiate)(struct key *key, const void *data, size_t datalen);
197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 /* update a key of this type (optional)
199 * - this method should call key_payload_reserve() to recalculate the
200 * quota consumption
201 * - the key must be locked against read when modifying
202 */
203 int (*update)(struct key *key, const void *data, size_t datalen);
204
205 /* match a key against a description */
206 int (*match)(const struct key *key, const void *desc);
207
208 /* clear the data from a key (optional) */
209 void (*destroy)(struct key *key);
210
211 /* describe a key */
212 void (*describe)(const struct key *key, struct seq_file *p);
213
214 /* read a key's data (optional)
215 * - permission checks will be done by the caller
216 * - the key's semaphore will be readlocked by the caller
217 * - should return the amount of data that could be read, no matter how
218 * much is copied into the buffer
219 * - shouldn't do the copy if the buffer is NULL
220 */
221 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
222
David Howellsb5f545c2006-01-08 01:02:47 -0800223 /* handle request_key() for this type instead of invoking
224 * /sbin/request-key (optional)
225 * - key is the key to instantiate
226 * - authkey is the authority to assume when instantiating this key
227 * - op is the operation to be done, usually "create"
228 * - the call must not return until the instantiation process has run
229 * its course
230 */
231 request_key_actor_t request_key;
232
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 /* internal fields */
234 struct list_head link; /* link in types list */
235};
236
237extern struct key_type key_type_keyring;
238
239extern int register_key_type(struct key_type *ktype);
240extern void unregister_key_type(struct key_type *ktype);
241
242extern struct key *key_alloc(struct key_type *type,
243 const char *desc,
244 uid_t uid, gid_t gid, key_perm_t perm,
245 int not_in_quota);
246extern int key_payload_reserve(struct key *key, size_t datalen);
247extern int key_instantiate_and_link(struct key *key,
248 const void *data,
249 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700250 struct key *keyring,
251 struct key *instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252extern int key_negate_and_link(struct key *key,
253 unsigned timeout,
David Howells3e301482005-06-23 22:00:56 -0700254 struct key *keyring,
255 struct key *instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256extern void key_revoke(struct key *key);
257extern void key_put(struct key *key);
258
259static inline struct key *key_get(struct key *key)
260{
261 if (key)
262 atomic_inc(&key->usage);
263 return key;
264}
265
David Howells664cceb2005-09-28 17:03:15 +0100266static inline void key_ref_put(key_ref_t key_ref)
267{
268 key_put(key_ref_to_ptr(key_ref));
269}
270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271extern struct key *request_key(struct key_type *type,
272 const char *description,
273 const char *callout_info);
274
275extern int key_validate(struct key *key);
276
David Howells664cceb2005-09-28 17:03:15 +0100277extern key_ref_t key_create_or_update(key_ref_t keyring,
278 const char *type,
279 const char *description,
280 const void *payload,
281 size_t plen,
282 int not_in_quota);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
David Howells664cceb2005-09-28 17:03:15 +0100284extern int key_update(key_ref_t key,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 const void *payload,
286 size_t plen);
287
288extern int key_link(struct key *keyring,
289 struct key *key);
290
291extern int key_unlink(struct key *keyring,
292 struct key *key);
293
294extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
295 int not_in_quota, struct key *dest);
296
297extern int keyring_clear(struct key *keyring);
298
David Howells664cceb2005-09-28 17:03:15 +0100299extern key_ref_t keyring_search(key_ref_t keyring,
300 struct key_type *type,
301 const char *description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303extern int keyring_add_key(struct key *keyring,
304 struct key *key);
305
306extern struct key *key_lookup(key_serial_t id);
307
David Howells76d8aea2005-06-23 22:00:49 -0700308extern void keyring_replace_payload(struct key *key, void *replacement);
309
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310#define key_serial(key) ((key) ? (key)->serial : 0)
311
312/*
313 * the userspace interface
314 */
315extern struct key root_user_keyring, root_session_keyring;
316extern int alloc_uid_keyring(struct user_struct *user);
317extern void switch_uid_keyring(struct user_struct *new_user);
318extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
319extern int copy_thread_group_keys(struct task_struct *tsk);
320extern void exit_keys(struct task_struct *tsk);
321extern void exit_thread_group_keys(struct signal_struct *tg);
322extern int suid_keys(struct task_struct *tsk);
323extern int exec_keys(struct task_struct *tsk);
324extern void key_fsuid_changed(struct task_struct *tsk);
325extern void key_fsgid_changed(struct task_struct *tsk);
326extern void key_init(void);
327
David Howells7888e7f2005-06-23 22:00:51 -0700328#define __install_session_keyring(tsk, keyring) \
329({ \
330 struct key *old_session = tsk->signal->session_keyring; \
331 tsk->signal->session_keyring = keyring; \
332 old_session; \
333})
334
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335#else /* CONFIG_KEYS */
336
337#define key_validate(k) 0
338#define key_serial(k) 0
David Howells7888e7f2005-06-23 22:00:51 -0700339#define key_get(k) ({ NULL; })
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340#define key_put(k) do { } while(0)
David Howells664cceb2005-09-28 17:03:15 +0100341#define key_ref_put(k) do { } while(0)
342#define make_key_ref(k) ({ NULL; })
343#define key_ref_to_ptr(k) ({ NULL; })
344#define is_key_possessed(k) 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345#define alloc_uid_keyring(u) 0
346#define switch_uid_keyring(u) do { } while(0)
David Howells7888e7f2005-06-23 22:00:51 -0700347#define __install_session_keyring(t, k) ({ NULL; })
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348#define copy_keys(f,t) 0
349#define copy_thread_group_keys(t) 0
350#define exit_keys(t) do { } while(0)
351#define exit_thread_group_keys(tg) do { } while(0)
352#define suid_keys(t) do { } while(0)
353#define exec_keys(t) do { } while(0)
354#define key_fsuid_changed(t) do { } while(0)
355#define key_fsgid_changed(t) do { } while(0)
356#define key_init() do { } while(0)
357
358#endif /* CONFIG_KEYS */
359#endif /* __KERNEL__ */
360#endif /* _LINUX_KEY_H */