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1da177e4 LT |
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> |
1da177e4 LT |
22 | #include <asm/atomic.h> |
23 | ||
24 | #ifdef __KERNEL__ | |
25 | ||
26 | /* key handle serial number */ | |
27 | typedef int32_t key_serial_t; | |
28 | ||
29 | /* key handle permissions mask */ | |
30 | typedef uint32_t key_perm_t; | |
31 | ||
32 | struct key; | |
33 | ||
34 | #ifdef CONFIG_KEYS | |
35 | ||
36 | #undef KEY_DEBUGGING | |
37 | ||
664cceb0 DH |
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 */ | |
43 | #define KEY_POS_ALL 0x1f000000 | |
44 | ||
45 | #define KEY_USR_VIEW 0x00010000 /* user permissions... */ | |
46 | #define KEY_USR_READ 0x00020000 | |
47 | #define KEY_USR_WRITE 0x00040000 | |
48 | #define KEY_USR_SEARCH 0x00080000 | |
49 | #define KEY_USR_LINK 0x00100000 | |
1da177e4 LT |
50 | #define KEY_USR_ALL 0x001f0000 |
51 | ||
52 | #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ | |
53 | #define KEY_GRP_READ 0x00000200 | |
54 | #define KEY_GRP_WRITE 0x00000400 | |
55 | #define KEY_GRP_SEARCH 0x00000800 | |
56 | #define KEY_GRP_LINK 0x00001000 | |
57 | #define KEY_GRP_ALL 0x00001f00 | |
58 | ||
59 | #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ | |
60 | #define KEY_OTH_READ 0x00000002 | |
61 | #define KEY_OTH_WRITE 0x00000004 | |
62 | #define KEY_OTH_SEARCH 0x00000008 | |
63 | #define KEY_OTH_LINK 0x00000010 | |
64 | #define KEY_OTH_ALL 0x0000001f | |
65 | ||
66 | struct seq_file; | |
67 | struct user_struct; | |
68 | struct signal_struct; | |
69 | ||
70 | struct key_type; | |
71 | struct key_owner; | |
72 | struct keyring_list; | |
73 | struct keyring_name; | |
74 | ||
664cceb0 DH |
75 | /*****************************************************************************/ |
76 | /* | |
77 | * key reference with possession attribute handling | |
78 | * | |
79 | * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually | |
80 | * defined. This is because we abuse the bottom bit of the reference to carry a | |
81 | * flag to indicate whether the calling process possesses that key in one of | |
82 | * its keyrings. | |
83 | * | |
84 | * the key_ref_t has been made a separate type so that the compiler can reject | |
85 | * attempts to dereference it without proper conversion. | |
86 | * | |
87 | * the three functions are used to assemble and disassemble references | |
88 | */ | |
89 | typedef struct __key_reference_with_attributes *key_ref_t; | |
90 | ||
91 | static inline key_ref_t make_key_ref(const struct key *key, | |
92 | unsigned long possession) | |
93 | { | |
94 | return (key_ref_t) ((unsigned long) key | possession); | |
95 | } | |
96 | ||
97 | static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) | |
98 | { | |
99 | return (struct key *) ((unsigned long) key_ref & ~1UL); | |
100 | } | |
101 | ||
102 | static inline unsigned long is_key_possessed(const key_ref_t key_ref) | |
103 | { | |
104 | return (unsigned long) key_ref & 1UL; | |
105 | } | |
106 | ||
1da177e4 LT |
107 | /*****************************************************************************/ |
108 | /* | |
109 | * authentication token / access credential / keyring | |
110 | * - types of key include: | |
111 | * - keyrings | |
112 | * - disk encryption IDs | |
113 | * - Kerberos TGTs and tickets | |
114 | */ | |
115 | struct key { | |
116 | atomic_t usage; /* number of references */ | |
117 | key_serial_t serial; /* key serial number */ | |
118 | struct rb_node serial_node; | |
119 | struct key_type *type; /* type of key */ | |
1da177e4 LT |
120 | struct rw_semaphore sem; /* change vs change sem */ |
121 | struct key_user *user; /* owner of this key */ | |
122 | time_t expiry; /* time at which key expires (or 0) */ | |
123 | uid_t uid; | |
124 | gid_t gid; | |
125 | key_perm_t perm; /* access permissions */ | |
126 | unsigned short quotalen; /* length added to quota */ | |
76d8aeab DH |
127 | unsigned short datalen; /* payload data length |
128 | * - may not match RCU dereferenced payload | |
129 | * - payload should contain own length | |
130 | */ | |
1da177e4 LT |
131 | |
132 | #ifdef KEY_DEBUGGING | |
133 | unsigned magic; | |
134 | #define KEY_DEBUG_MAGIC 0x18273645u | |
135 | #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu | |
136 | #endif | |
137 | ||
76d8aeab DH |
138 | unsigned long flags; /* status flags (change with bitops) */ |
139 | #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ | |
140 | #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ | |
141 | #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ | |
142 | #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ | |
143 | #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ | |
144 | #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ | |
145 | ||
1da177e4 LT |
146 | /* the description string |
147 | * - this is used to match a key against search criteria | |
148 | * - this should be a printable string | |
149 | * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" | |
150 | */ | |
151 | char *description; | |
152 | ||
153 | /* type specific data | |
154 | * - this is used by the keyring type to index the name | |
155 | */ | |
156 | union { | |
157 | struct list_head link; | |
158 | } type_data; | |
159 | ||
160 | /* key data | |
161 | * - this is used to hold the data actually used in cryptography or | |
162 | * whatever | |
163 | */ | |
164 | union { | |
165 | unsigned long value; | |
166 | void *data; | |
167 | struct keyring_list *subscriptions; | |
168 | } payload; | |
169 | }; | |
170 | ||
171 | /*****************************************************************************/ | |
172 | /* | |
173 | * kernel managed key type definition | |
174 | */ | |
175 | struct key_type { | |
176 | /* name of the type */ | |
177 | const char *name; | |
178 | ||
179 | /* default payload length for quota precalculation (optional) | |
180 | * - this can be used instead of calling key_payload_reserve(), that | |
181 | * function only needs to be called if the real datalen is different | |
182 | */ | |
183 | size_t def_datalen; | |
184 | ||
185 | /* instantiate a key of this type | |
186 | * - this method should call key_payload_reserve() to determine if the | |
187 | * user's quota will hold the payload | |
188 | */ | |
189 | int (*instantiate)(struct key *key, const void *data, size_t datalen); | |
190 | ||
191 | /* duplicate a key of this type (optional) | |
192 | * - the source key will be locked against change | |
193 | * - the new description will be attached | |
194 | * - the quota will have been adjusted automatically from | |
195 | * source->quotalen | |
196 | */ | |
197 | int (*duplicate)(struct key *key, const struct key *source); | |
198 | ||
199 | /* update a key of this type (optional) | |
200 | * - this method should call key_payload_reserve() to recalculate the | |
201 | * quota consumption | |
202 | * - the key must be locked against read when modifying | |
203 | */ | |
204 | int (*update)(struct key *key, const void *data, size_t datalen); | |
205 | ||
206 | /* match a key against a description */ | |
207 | int (*match)(const struct key *key, const void *desc); | |
208 | ||
209 | /* clear the data from a key (optional) */ | |
210 | void (*destroy)(struct key *key); | |
211 | ||
212 | /* describe a key */ | |
213 | void (*describe)(const struct key *key, struct seq_file *p); | |
214 | ||
215 | /* read a key's data (optional) | |
216 | * - permission checks will be done by the caller | |
217 | * - the key's semaphore will be readlocked by the caller | |
218 | * - should return the amount of data that could be read, no matter how | |
219 | * much is copied into the buffer | |
220 | * - shouldn't do the copy if the buffer is NULL | |
221 | */ | |
222 | long (*read)(const struct key *key, char __user *buffer, size_t buflen); | |
223 | ||
224 | /* internal fields */ | |
225 | struct list_head link; /* link in types list */ | |
226 | }; | |
227 | ||
228 | extern struct key_type key_type_keyring; | |
229 | ||
230 | extern int register_key_type(struct key_type *ktype); | |
231 | extern void unregister_key_type(struct key_type *ktype); | |
232 | ||
233 | extern struct key *key_alloc(struct key_type *type, | |
234 | const char *desc, | |
235 | uid_t uid, gid_t gid, key_perm_t perm, | |
236 | int not_in_quota); | |
237 | extern int key_payload_reserve(struct key *key, size_t datalen); | |
238 | extern int key_instantiate_and_link(struct key *key, | |
239 | const void *data, | |
240 | size_t datalen, | |
3e30148c DH |
241 | struct key *keyring, |
242 | struct key *instkey); | |
1da177e4 LT |
243 | extern int key_negate_and_link(struct key *key, |
244 | unsigned timeout, | |
3e30148c DH |
245 | struct key *keyring, |
246 | struct key *instkey); | |
1da177e4 LT |
247 | extern void key_revoke(struct key *key); |
248 | extern void key_put(struct key *key); | |
249 | ||
250 | static inline struct key *key_get(struct key *key) | |
251 | { | |
252 | if (key) | |
253 | atomic_inc(&key->usage); | |
254 | return key; | |
255 | } | |
256 | ||
664cceb0 DH |
257 | static inline void key_ref_put(key_ref_t key_ref) |
258 | { | |
259 | key_put(key_ref_to_ptr(key_ref)); | |
260 | } | |
261 | ||
1da177e4 LT |
262 | extern struct key *request_key(struct key_type *type, |
263 | const char *description, | |
264 | const char *callout_info); | |
265 | ||
266 | extern int key_validate(struct key *key); | |
267 | ||
664cceb0 DH |
268 | extern key_ref_t key_create_or_update(key_ref_t keyring, |
269 | const char *type, | |
270 | const char *description, | |
271 | const void *payload, | |
272 | size_t plen, | |
273 | int not_in_quota); | |
1da177e4 | 274 | |
664cceb0 | 275 | extern int key_update(key_ref_t key, |
1da177e4 LT |
276 | const void *payload, |
277 | size_t plen); | |
278 | ||
279 | extern int key_link(struct key *keyring, | |
280 | struct key *key); | |
281 | ||
282 | extern int key_unlink(struct key *keyring, | |
283 | struct key *key); | |
284 | ||
285 | extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, | |
286 | int not_in_quota, struct key *dest); | |
287 | ||
288 | extern int keyring_clear(struct key *keyring); | |
289 | ||
664cceb0 DH |
290 | extern key_ref_t keyring_search(key_ref_t keyring, |
291 | struct key_type *type, | |
292 | const char *description); | |
1da177e4 | 293 | |
1da177e4 LT |
294 | extern int keyring_add_key(struct key *keyring, |
295 | struct key *key); | |
296 | ||
297 | extern struct key *key_lookup(key_serial_t id); | |
298 | ||
76d8aeab DH |
299 | extern void keyring_replace_payload(struct key *key, void *replacement); |
300 | ||
1da177e4 LT |
301 | #define key_serial(key) ((key) ? (key)->serial : 0) |
302 | ||
303 | /* | |
304 | * the userspace interface | |
305 | */ | |
306 | extern struct key root_user_keyring, root_session_keyring; | |
307 | extern int alloc_uid_keyring(struct user_struct *user); | |
308 | extern void switch_uid_keyring(struct user_struct *new_user); | |
309 | extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk); | |
310 | extern int copy_thread_group_keys(struct task_struct *tsk); | |
311 | extern void exit_keys(struct task_struct *tsk); | |
312 | extern void exit_thread_group_keys(struct signal_struct *tg); | |
313 | extern int suid_keys(struct task_struct *tsk); | |
314 | extern int exec_keys(struct task_struct *tsk); | |
315 | extern void key_fsuid_changed(struct task_struct *tsk); | |
316 | extern void key_fsgid_changed(struct task_struct *tsk); | |
317 | extern void key_init(void); | |
318 | ||
7888e7ff DH |
319 | #define __install_session_keyring(tsk, keyring) \ |
320 | ({ \ | |
321 | struct key *old_session = tsk->signal->session_keyring; \ | |
322 | tsk->signal->session_keyring = keyring; \ | |
323 | old_session; \ | |
324 | }) | |
325 | ||
1da177e4 LT |
326 | #else /* CONFIG_KEYS */ |
327 | ||
328 | #define key_validate(k) 0 | |
329 | #define key_serial(k) 0 | |
7888e7ff | 330 | #define key_get(k) ({ NULL; }) |
1da177e4 | 331 | #define key_put(k) do { } while(0) |
664cceb0 DH |
332 | #define key_ref_put(k) do { } while(0) |
333 | #define make_key_ref(k) ({ NULL; }) | |
334 | #define key_ref_to_ptr(k) ({ NULL; }) | |
335 | #define is_key_possessed(k) 0 | |
1da177e4 LT |
336 | #define alloc_uid_keyring(u) 0 |
337 | #define switch_uid_keyring(u) do { } while(0) | |
7888e7ff | 338 | #define __install_session_keyring(t, k) ({ NULL; }) |
1da177e4 LT |
339 | #define copy_keys(f,t) 0 |
340 | #define copy_thread_group_keys(t) 0 | |
341 | #define exit_keys(t) do { } while(0) | |
342 | #define exit_thread_group_keys(tg) do { } while(0) | |
343 | #define suid_keys(t) do { } while(0) | |
344 | #define exec_keys(t) do { } while(0) | |
345 | #define key_fsuid_changed(t) do { } while(0) | |
346 | #define key_fsgid_changed(t) do { } while(0) | |
347 | #define key_init() do { } while(0) | |
348 | ||
349 | #endif /* CONFIG_KEYS */ | |
350 | #endif /* __KERNEL__ */ | |
351 | #endif /* _LINUX_KEY_H */ |