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/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 <asm/atomic.h>
25
26 #ifdef __KERNEL__
27
28 /* key handle serial number */
29 typedef int32_t key_serial_t;
30
31 /* key handle permissions mask */
32 typedef uint32_t key_perm_t;
33
34 struct key;
35
36 #ifdef CONFIG_KEYS
37
38 #undef KEY_DEBUGGING
39
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
47
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
55
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
63
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
71
72 #define KEY_PERM_UNDEF 0xffffffff
73
74 struct seq_file;
75 struct user_struct;
76 struct signal_struct;
77 struct cred;
78
79 struct key_type;
80 struct key_owner;
81 struct keyring_list;
82 struct keyring_name;
83
84 /*****************************************************************************/
85 /*
86 * key reference with possession attribute handling
87 *
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
91 * its keyrings.
92 *
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.
95 *
96 * the three functions are used to assemble and disassemble references
97 */
98 typedef struct __key_reference_with_attributes *key_ref_t;
99
make_key_ref(const struct key * key,unsigned long possession)100 static inline key_ref_t make_key_ref(const struct key *key,
101 unsigned long possession)
102 {
103 return (key_ref_t) ((unsigned long) key | possession);
104 }
105
key_ref_to_ptr(const key_ref_t key_ref)106 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
107 {
108 return (struct key *) ((unsigned long) key_ref & ~1UL);
109 }
110
is_key_possessed(const key_ref_t key_ref)111 static inline unsigned long is_key_possessed(const key_ref_t key_ref)
112 {
113 return (unsigned long) key_ref & 1UL;
114 }
115
116 /*****************************************************************************/
117 /*
118 * authentication token / access credential / keyring
119 * - types of key include:
120 * - keyrings
121 * - disk encryption IDs
122 * - Kerberos TGTs and tickets
123 */
124 struct key {
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 */
132 union {
133 time_t expiry; /* time at which key expires (or 0) */
134 time_t revoked_at; /* time at which key was revoked */
135 };
136 uid_t uid;
137 gid_t gid;
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
143 */
144
145 #ifdef KEY_DEBUGGING
146 unsigned magic;
147 #define KEY_DEBUG_MAGIC 0x18273645u
148 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
149 #endif
150
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
159 /* the description string
160 * - this is used to match a key against search criteria
161 * - this should be a printable string
162 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
163 */
164 char *description;
165
166 /* type specific data
167 * - this is used by the keyring type to index the name
168 */
169 union {
170 struct list_head link;
171 unsigned long x[2];
172 void *p[2];
173 int reject_error;
174 } type_data;
175
176 /* key data
177 * - this is used to hold the data actually used in cryptography or
178 * whatever
179 */
180 union {
181 unsigned long value;
182 void __rcu *rcudata;
183 void *data;
184 struct keyring_list __rcu *subscriptions;
185 } payload;
186 };
187
188 extern struct key *key_alloc(struct key_type *type,
189 const char *desc,
190 uid_t uid, gid_t gid,
191 const struct cred *cred,
192 key_perm_t perm,
193 unsigned long flags);
194
195
196 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
197 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
198 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
199
200 extern void key_revoke(struct key *key);
201 extern void key_put(struct key *key);
202
key_get(struct key * key)203 static inline struct key *key_get(struct key *key)
204 {
205 if (key)
206 atomic_inc(&key->usage);
207 return key;
208 }
209
key_ref_put(key_ref_t key_ref)210 static inline void key_ref_put(key_ref_t key_ref)
211 {
212 key_put(key_ref_to_ptr(key_ref));
213 }
214
215 extern struct key *request_key(struct key_type *type,
216 const char *description,
217 const char *callout_info);
218
219 extern struct key *request_key_with_auxdata(struct key_type *type,
220 const char *description,
221 const void *callout_info,
222 size_t callout_len,
223 void *aux);
224
225 extern struct key *request_key_async(struct key_type *type,
226 const char *description,
227 const void *callout_info,
228 size_t callout_len);
229
230 extern struct key *request_key_async_with_auxdata(struct key_type *type,
231 const char *description,
232 const void *callout_info,
233 size_t callout_len,
234 void *aux);
235
236 extern int wait_for_key_construction(struct key *key, bool intr);
237
238 extern int key_validate(struct key *key);
239
240 extern key_ref_t key_create_or_update(key_ref_t keyring,
241 const char *type,
242 const char *description,
243 const void *payload,
244 size_t plen,
245 key_perm_t perm,
246 unsigned long flags);
247
248 extern int key_update(key_ref_t key,
249 const void *payload,
250 size_t plen);
251
252 extern int key_link(struct key *keyring,
253 struct key *key);
254
255 extern int key_unlink(struct key *keyring,
256 struct key *key);
257
258 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
259 const struct cred *cred,
260 unsigned long flags,
261 struct key *dest);
262
263 extern int keyring_clear(struct key *keyring);
264
265 extern key_ref_t keyring_search(key_ref_t keyring,
266 struct key_type *type,
267 const char *description);
268
269 extern int keyring_add_key(struct key *keyring,
270 struct key *key);
271
272 extern struct key *key_lookup(key_serial_t id);
273
key_serial(struct key * key)274 static inline key_serial_t key_serial(struct key *key)
275 {
276 return key ? key->serial : 0;
277 }
278
279 #define rcu_dereference_key(KEY) \
280 (rcu_dereference_protected((KEY)->payload.rcudata, \
281 rwsem_is_locked(&((struct key *)(KEY))->sem)))
282
283 #ifdef CONFIG_SYSCTL
284 extern ctl_table key_sysctls[];
285 #endif
286
287 extern void key_replace_session_keyring(void);
288
289 /*
290 * the userspace interface
291 */
292 extern int install_thread_keyring_to_cred(struct cred *cred);
293 extern void key_fsuid_changed(struct task_struct *tsk);
294 extern void key_fsgid_changed(struct task_struct *tsk);
295 extern void key_init(void);
296
297 #else /* CONFIG_KEYS */
298
299 #define key_validate(k) 0
300 #define key_serial(k) 0
301 #define key_get(k) ({ NULL; })
302 #define key_revoke(k) do { } while(0)
303 #define key_put(k) do { } while(0)
304 #define key_ref_put(k) do { } while(0)
305 #define make_key_ref(k, p) NULL
306 #define key_ref_to_ptr(k) NULL
307 #define is_key_possessed(k) 0
308 #define key_fsuid_changed(t) do { } while(0)
309 #define key_fsgid_changed(t) do { } while(0)
310 #define key_init() do { } while(0)
311 #define key_replace_session_keyring() do { } while(0)
312
313 #endif /* CONFIG_KEYS */
314 #endif /* __KERNEL__ */
315 #endif /* _LINUX_KEY_H */
316