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1 | /* Authentication token and access key management | |
2 | * | |
3 | * Copyright (C) 2004, 2007 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/security/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> | |
21 | #include <linux/rcupdate.h> | |
22 | #include <linux/sysctl.h> | |
23 | #include <linux/rwsem.h> | |
24 | #include <linux/atomic.h> | |
25 | ||
26 | #ifdef __KERNEL__ | |
27 | #include <linux/uidgid.h> | |
28 | ||
29 | /* key handle serial number */ | |
30 | typedef int32_t key_serial_t; | |
31 | ||
32 | /* key handle permissions mask */ | |
33 | typedef uint32_t key_perm_t; | |
34 | ||
35 | struct key; | |
36 | ||
37 | #ifdef CONFIG_KEYS | |
38 | ||
39 | #undef KEY_DEBUGGING | |
40 | ||
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 | |
48 | ||
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 | |
56 | ||
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 | |
64 | ||
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 | |
72 | ||
73 | #define KEY_PERM_UNDEF 0xffffffff | |
74 | ||
75 | struct seq_file; | |
76 | struct user_struct; | |
77 | struct signal_struct; | |
78 | struct cred; | |
79 | ||
80 | struct key_type; | |
81 | struct key_owner; | |
82 | struct keyring_list; | |
83 | struct keyring_name; | |
84 | ||
85 | /*****************************************************************************/ | |
86 | /* | |
87 | * key reference with possession attribute handling | |
88 | * | |
89 | * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually | |
90 | * defined. This is because we abuse the bottom bit of the reference to carry a | |
91 | * flag to indicate whether the calling process possesses that key in one of | |
92 | * its keyrings. | |
93 | * | |
94 | * the key_ref_t has been made a separate type so that the compiler can reject | |
95 | * attempts to dereference it without proper conversion. | |
96 | * | |
97 | * the three functions are used to assemble and disassemble references | |
98 | */ | |
99 | typedef struct __key_reference_with_attributes *key_ref_t; | |
100 | ||
101 | static inline key_ref_t make_key_ref(const struct key *key, | |
102 | unsigned long possession) | |
103 | { | |
104 | return (key_ref_t) ((unsigned long) key | possession); | |
105 | } | |
106 | ||
107 | static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) | |
108 | { | |
109 | return (struct key *) ((unsigned long) key_ref & ~1UL); | |
110 | } | |
111 | ||
112 | static inline unsigned long is_key_possessed(const key_ref_t key_ref) | |
113 | { | |
114 | return (unsigned long) key_ref & 1UL; | |
115 | } | |
116 | ||
117 | /*****************************************************************************/ | |
118 | /* | |
119 | * authentication token / access credential / keyring | |
120 | * - types of key include: | |
121 | * - keyrings | |
122 | * - disk encryption IDs | |
123 | * - Kerberos TGTs and tickets | |
124 | */ | |
125 | struct key { | |
126 | atomic_t usage; /* number of references */ | |
127 | key_serial_t serial; /* key serial number */ | |
128 | union { | |
129 | struct list_head graveyard_link; | |
130 | struct rb_node serial_node; | |
131 | }; | |
132 | struct key_type *type; /* type of key */ | |
133 | struct rw_semaphore sem; /* change vs change sem */ | |
134 | struct key_user *user; /* owner of this key */ | |
135 | void *security; /* security data for this key */ | |
136 | union { | |
137 | time_t expiry; /* time at which key expires (or 0) */ | |
138 | time_t revoked_at; /* time at which key was revoked */ | |
139 | }; | |
140 | time_t last_used_at; /* last time used for LRU keyring discard */ | |
141 | kuid_t uid; | |
142 | kgid_t gid; | |
143 | key_perm_t perm; /* access permissions */ | |
144 | unsigned short quotalen; /* length added to quota */ | |
145 | unsigned short datalen; /* payload data length | |
146 | * - may not match RCU dereferenced payload | |
147 | * - payload should contain own length | |
148 | */ | |
149 | ||
150 | #ifdef KEY_DEBUGGING | |
151 | unsigned magic; | |
152 | #define KEY_DEBUG_MAGIC 0x18273645u | |
153 | #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu | |
154 | #endif | |
155 | ||
156 | unsigned long flags; /* status flags (change with bitops) */ | |
157 | #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */ | |
158 | #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */ | |
159 | #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */ | |
160 | #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */ | |
161 | #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */ | |
162 | #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */ | |
163 | #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ | |
164 | #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ | |
165 | ||
166 | /* the description string | |
167 | * - this is used to match a key against search criteria | |
168 | * - this should be a printable string | |
169 | * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" | |
170 | */ | |
171 | char *description; | |
172 | ||
173 | /* type specific data | |
174 | * - this is used by the keyring type to index the name | |
175 | */ | |
176 | union { | |
177 | struct list_head link; | |
178 | unsigned long x[2]; | |
179 | void *p[2]; | |
180 | int reject_error; | |
181 | } type_data; | |
182 | ||
183 | /* key data | |
184 | * - this is used to hold the data actually used in cryptography or | |
185 | * whatever | |
186 | */ | |
187 | union { | |
188 | unsigned long value; | |
189 | void __rcu *rcudata; | |
190 | void *data; | |
191 | struct keyring_list __rcu *subscriptions; | |
192 | } payload; | |
193 | }; | |
194 | ||
195 | extern struct key *key_alloc(struct key_type *type, | |
196 | const char *desc, | |
197 | kuid_t uid, kgid_t gid, | |
198 | const struct cred *cred, | |
199 | key_perm_t perm, | |
200 | unsigned long flags); | |
201 | ||
202 | ||
203 | #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ | |
204 | #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ | |
205 | #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ | |
206 | ||
207 | extern void key_revoke(struct key *key); | |
208 | extern void key_invalidate(struct key *key); | |
209 | extern void key_put(struct key *key); | |
210 | ||
211 | static inline struct key *key_get(struct key *key) | |
212 | { | |
213 | if (key) | |
214 | atomic_inc(&key->usage); | |
215 | return key; | |
216 | } | |
217 | ||
218 | static inline void key_ref_put(key_ref_t key_ref) | |
219 | { | |
220 | key_put(key_ref_to_ptr(key_ref)); | |
221 | } | |
222 | ||
223 | extern struct key *request_key(struct key_type *type, | |
224 | const char *description, | |
225 | const char *callout_info); | |
226 | ||
227 | extern struct key *request_key_with_auxdata(struct key_type *type, | |
228 | const char *description, | |
229 | const void *callout_info, | |
230 | size_t callout_len, | |
231 | void *aux); | |
232 | ||
233 | extern struct key *request_key_async(struct key_type *type, | |
234 | const char *description, | |
235 | const void *callout_info, | |
236 | size_t callout_len); | |
237 | ||
238 | extern struct key *request_key_async_with_auxdata(struct key_type *type, | |
239 | const char *description, | |
240 | const void *callout_info, | |
241 | size_t callout_len, | |
242 | void *aux); | |
243 | ||
244 | extern int wait_for_key_construction(struct key *key, bool intr); | |
245 | ||
246 | extern int key_validate(const struct key *key); | |
247 | ||
248 | extern key_ref_t key_create_or_update(key_ref_t keyring, | |
249 | const char *type, | |
250 | const char *description, | |
251 | const void *payload, | |
252 | size_t plen, | |
253 | key_perm_t perm, | |
254 | unsigned long flags); | |
255 | ||
256 | extern int key_update(key_ref_t key, | |
257 | const void *payload, | |
258 | size_t plen); | |
259 | ||
260 | extern int key_link(struct key *keyring, | |
261 | struct key *key); | |
262 | ||
263 | extern int key_unlink(struct key *keyring, | |
264 | struct key *key); | |
265 | ||
266 | extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, | |
267 | const struct cred *cred, | |
268 | key_perm_t perm, | |
269 | unsigned long flags, | |
270 | struct key *dest); | |
271 | ||
272 | extern int keyring_clear(struct key *keyring); | |
273 | ||
274 | extern key_ref_t keyring_search(key_ref_t keyring, | |
275 | struct key_type *type, | |
276 | const char *description); | |
277 | ||
278 | extern int keyring_add_key(struct key *keyring, | |
279 | struct key *key); | |
280 | ||
281 | extern struct key *key_lookup(key_serial_t id); | |
282 | ||
283 | static inline key_serial_t key_serial(const struct key *key) | |
284 | { | |
285 | return key ? key->serial : 0; | |
286 | } | |
287 | ||
288 | extern void key_set_timeout(struct key *, unsigned); | |
289 | ||
290 | /** | |
291 | * key_is_instantiated - Determine if a key has been positively instantiated | |
292 | * @key: The key to check. | |
293 | * | |
294 | * Return true if the specified key has been positively instantiated, false | |
295 | * otherwise. | |
296 | */ | |
297 | static inline bool key_is_instantiated(const struct key *key) | |
298 | { | |
299 | return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && | |
300 | !test_bit(KEY_FLAG_NEGATIVE, &key->flags); | |
301 | } | |
302 | ||
303 | #define rcu_dereference_key(KEY) \ | |
304 | (rcu_dereference_protected((KEY)->payload.rcudata, \ | |
305 | rwsem_is_locked(&((struct key *)(KEY))->sem))) | |
306 | ||
307 | #define rcu_assign_keypointer(KEY, PAYLOAD) \ | |
308 | do { \ | |
309 | rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \ | |
310 | } while (0) | |
311 | ||
312 | #ifdef CONFIG_SYSCTL | |
313 | extern ctl_table key_sysctls[]; | |
314 | #endif | |
315 | /* | |
316 | * the userspace interface | |
317 | */ | |
318 | extern int install_thread_keyring_to_cred(struct cred *cred); | |
319 | extern void key_fsuid_changed(struct task_struct *tsk); | |
320 | extern void key_fsgid_changed(struct task_struct *tsk); | |
321 | extern void key_init(void); | |
322 | ||
323 | #else /* CONFIG_KEYS */ | |
324 | ||
325 | #define key_validate(k) 0 | |
326 | #define key_serial(k) 0 | |
327 | #define key_get(k) ({ NULL; }) | |
328 | #define key_revoke(k) do { } while(0) | |
329 | #define key_invalidate(k) do { } while(0) | |
330 | #define key_put(k) do { } while(0) | |
331 | #define key_ref_put(k) do { } while(0) | |
332 | #define make_key_ref(k, p) NULL | |
333 | #define key_ref_to_ptr(k) NULL | |
334 | #define is_key_possessed(k) 0 | |
335 | #define key_fsuid_changed(t) do { } while(0) | |
336 | #define key_fsgid_changed(t) do { } while(0) | |
337 | #define key_init() do { } while(0) | |
338 | ||
339 | #endif /* CONFIG_KEYS */ | |
340 | #endif /* __KERNEL__ */ | |
341 | #endif /* _LINUX_KEY_H */ |